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OPS - History and Outlook

OPS is an adaptation of the English-language International Classification of Procedures in Medicine (ICPM) by WHO. The German version of the ICPM resulted from the translation and expansion of the Dutch version ICPM-DE (Dutch Extension) and was further developed into OPS-301 and then OPS.

Version history and Announcements

This overview shows periods of validity, areas of application and legal foundations for the various versions of OPS (OPS-301); in addition, it also contains references to the publication in the Federal Gazette of the dates that respective version became effective

Version history and Announcements


The need for an international classification of medical measures had been recognised as early as 1971. In 1978, WHO thus published its International Classification of Procedures in Medicine (ICPM). This was limited to surgical procedures. ICPM is part of the group of international health-related classifications. Because of the dynamics of medical-technical progress, the classification was costly to maintain and update; difficulties arose in international coordination. For that reason, work on the ICPM ceased in 1989. However, work on country-specific versions on a national level continued.

ICHI as the successor to the ICPM

In recent years, WHO has worked on a new classification of health interventions. The aim of this work is to create an internationally agreed classification that can be used for comparison and statistical exchange. For countries that do not yet have their own procedural classification, this new ICHI (International Classification of Health Interventions) is intended to be easily expandable. This new classification is also intended to cover traditional nedicine and measures taken by public healthcare services.

OPS-301: Version 1.0 to version 2.1

The German version of the ICPM resulted from the translation and expansion of the Dutch version ICPM-DE (Dutch Extension) and further developed into OPS-301. Of the 9 chapters of ICPM-DE, chapters 2,3,4,6 and 7 were omitted. OPS-301 version 1.0 was published in1994 by DIMDI on behalf of the Federal Ministry of Health (BMG) and used in inpatient care from 1995.

OPS-301 is a mainly numerical code with a monohierarchical structure, initially comprising 5 hierarchical levels. The four chapters in version 1.0 covered surgical prcedures (Ch. 5) as well as diagnostic (Ch. 1), non-surgical therapeutic (Ch. 8) and ancillary measures (Ch. 9).

The purpose of OPS-301 was greater transparency of services and costs. Its use to encode measures provided by hospitals was stipulated by the German Health Care Structure Act ("Gesundheitsstrukturgesetz GSG") and § 301 SGB V (Code of Soical Law Part V, "Sozialgesetzbuch Fünftes Buch"). OPS-301 permitted the billing of special reimbursement rates and case-based flat-rate payment of the old remuneration system as well as billing in accordance with the new G-DRG case-based fixed sum system, and it supported quality assurance documentation pursuant to § 137 SGB V.

In 2001, at the suggestion of the National Board for Classification in Health Care (KKG), the OPS Working Group (AG OPS) was set up at the DIMDI with representatives of all organisations involved with the KKG, in order to reach a consensus on the amendment required for OPS-301.

Version 2.0 was the first to include Chapter 3: Imaging Diagnostics

Versions 1.0, 1.1, 2.0 and 2.1 of OPS 301 were used from 1995 to 2003 exclusively for the encoding of surgical interventions in inpatient care.

Optional OPS: Extended catalogue

From version 2.1 (from mid-2003), OPS-301 was complemented by an unofficial extended catalogue to support the further development of OPS in relation to the G-DRG case-based fix sum system. This was also referred to as the optional OPS. The optional OPS was discontinued in 2009.

Optional OPS

OPS: Version 2004 to current version

From version 2004, OPS-301 has been continued as OPS. As part of a structured annual proposal procedure, it is developed further by the self-administration partners represented in the OPS Working Group under the lead management of the DIMDI and published annually. The most significant content changes compared with the previous version are highlighted in a commentary in the preface to the respective Tabular List , the individual changes are listed in the list of changes.

2004 was the first publication of an Alphabetical Index to complement OPS. Since 2004, OPS has been used generally to encode medical procedures in inpatient hospital care.

Since 2005, OPS has also been used for outpatient surgical interventions.

In 2006, the chapter "Medikamente" (Drugs, medicaments and biological agents) was included; until then, medicines could only be considered from regularly updated chemotherapeutic lists.

In 2009, the optional OPS was discontinued and its codes either transferred to the official catalogue or deleted.

In 2010, OPS was first published in the WHO standard ClaML format.

In 2011, the ASCII book format was discontinued.

Continuous development and improvement

OPS is further developed and improved through a structured and transparent proposal procedure and is currently revised on an annual basis.

Proposal procedure OPS